This is more like a toggle clamp in that you slide the moving jaw into place then squeeze to apply the force. To relieve the pressure you pull up on the end of the lever and it uses a cam action to aid in the release. This is not some sort of clamp that pulls loose stuff together, it needs to be snug before you clamp, in other words it has limited travel during engagement. It has an adjustment for clamping force, a dial that gets you up to a claimed 660 pounds of clamping force. It is mostly metal, and that is a good thing, well unless you don't like the weight, they are heavy.
I went with the smallest version, 6" and for most things this will do me fine but I do expect to add at least a second one of this size and possibly a pair of the 12". They are not cheap, the 6" is $22 and 12" $25. I do hope they put them on sale or give me a discount coupon at some point to buy the rest.
Long term use is still a question, while I had these all of about 8 days and only played with them a couple of times over those days I can not say how well they will do in the long term. I can say so far so good.
I previously did a mini review of the DuoKlamp, a very different type from this and I'm glad for the two very different functions they provide. You can find that here:
As you know you can never have too many clamps.